Historical typefaces (likepoluustav (semi-uncial), a standard font style for theChurch Slavonic typography) and old manuscripts represent several additional glyph variants of Cyrillic O, both for decorative and orthographic (sometimes also "hieroglyphic"[1]) purposes, namely:
broad variant (Ѻ/ѻ), used mostly as a word initial letter (seeBroad On for more details);
narrow variant, ᲂ, being used now in Synodal Church Slavonic editions as the first element of digraph Oy/oy (seeUk (Cyrillic) for more details), and in the editions ofOld Believers for unstressed "o" as well;
variant with a cross inside (Crossed O), Ꚛ, used in certain manuscripts as the initial letter of wordsокрестъ 'around, nearby' (the root of this Slavonic word,крест, means 'cross') andокругъ 'district, neighbourhood' with their derivatives;
"eyed" variant (Monocular O) with a dot inside (Ꙩ/ꙩ), used in certain manuscripts in spelling of wordоко 'eye' and its derivatives. In many other texts, including thebirchbark letters, the monocular O was not used as a hieroglyph but largely as a synonym ofBroad On signalling the word-initial position;
"two-eyed" variants (Binocular O) with two dots inside (Ꙫ/ꙫ or Ꙭ/ꙭ), alsodouble "O" without dots inside were used in certain manuscripts in spelling of dual/plural forms of the words with the same root 'eye';
"many-eyed" variant (Multiocular O), ꙮ, used in certain manuscripts in spelling of the same root when embedded into wordмногоочитый 'many-eyed' (an attribute ofseraphim).
InRussian, O is used word-initially, after another vowel, and after non-palatalized consonants. Because of avowel reduction processes, the Russian/o/ phoneme may have a number of pronunciations in unstressed syllables, including[ɐ] and[ə].
